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Watanabe, H.

Publications and source records attributed to Watanabe, H..

At least 19 recordsLinked to original sources

Seven gut microbiome types across two Japanese cohorts defined by co-abundance-based microbial guilds and associated with host physiology

Intensive efforts have been made to capture structural features of the gut microbiome for assessing microbiota status in relation to host health. However, gut microbiome function emerges not only from individual microbial taxa but also from their organization into ecological guilds, complicating microbiome structure-function relationships. To address this challenge, we applied a co-abundance-based analytical framework to identify gut microbiome types (GMTs) across a discovery cohort (D-cohort) and an independent validation cohort (V-cohort) of Japanese adults. Using paired fecal samples collected one month apart from 116 participants in the D-cohort, we identified 27 co-abundance groups (CAGs) based on 16S rRNA amplicon sequence variants. These CAGs defined seven GMTs (MT-1 to MT-7) with characteristic short-chain fatty acid and bile acid profiles. The GMTs showed temporal stability, with more than 70% of participants remaining in the same GMT across sampling points. The 27-CAG framework classified 404 participants in the independent V-cohort into the seven GMTs, which represented reproducible microbial ecological states across cohorts. MT-4 exhibited dysbiosis-like features, including reduced microbial diversity, depletion of Faecalibacterium and butyrate, and enrichment of inflammation-associated taxa, and was associated with higher alcohol consumption and elevated {gamma}-glutamyl transferase levels. In contrast, Bifidobacterium-enriched MT-5 was associated with favorable renal function profiles. Collectively, co-abundance-defined microbial guilds capture coherent ecological and functional states of the gut microbiota, providing a transferable framework for linking gut microbiome organization to host physiology beyond conventional taxonomy-based classification.

microbiology↗

Structural mechanism defining product specificity in glycoside hydrolase family 66 cycloisomaltotetraose glucanotransferase

Cyclic oligosaccharides possess industrial advantages, including molecular encapsulation capability and high physicochemical stability, owing to the absence of a reducing end. Recently, a novel cyclic tetrasaccharide, cycloisomaltotetraose (CI4), consisting of four -1,6-linked glucose units, and the enzymes responsible for its synthesis, cycloisomaltotetraose glucanotransferases (CI4Tases), were discovered. Unlike known cycloisomaltooligosaccharide glucanotransferases (CITases) that yield a wide distribution of cyclic products with a degree of polymerization (DP) of 7 or higher, CI4Tases strictly produce CI4. To elucidate the molecular mechanism underlying this strict DP4 specificity, we determined the crystal structures of CI4Tase from Agreia sp. D1110, in its ligand-free form, as well as in complex with the linear hydrolysis product isomaltotetraose (IG4) and with CI4. Structural comparisons revealed that a loop (M247 to R251) blocks the region corresponding to the -5 subsite of typical CITases, narrowing the substrate-binding pocket. This "molecular ruler" mechanism ensures that only a glycan chain of exactly four glucose units is accommodated for cyclization. Among mutants of the residue positioned at the center of bound CI4, the formation of by-products other than CI4 was significantly suppressed in F245L, F245A, and F245W. While the cyclization activity of all F245 mutants decreased, the CI4 hydrolysis activity of these three mutants was also significantly reduced, resulting in an increased specificity for cyclic sugar production. These findings elucidate the strict size-control mechanism of CI4Tase and provide a structural foundation for engineering cycloisomaltooligosaccharide-producing enzymes with optimized transglycosylation efficiency and specificity for industrial applications.

biochemistry↗

Natriuretic Peptide Augmentation Attenuates Renin Cell Hyperactivation and Afferent Arteriolar Hypertrophy During Long-Term Renin-Angiotensin System Inhibition

BACKGROUNDChronic renin-angiotensin system (RAS) inhibition activates renin cells and induces afferent arteriolar hypertrophy, a maladaptive vascular response that may contribute to nephrosclerosis-like renal injury. Although genetic or cell ablation approaches have shown that renin cells are required for this remodeling, no pharmacological strategy to restrain hyperactivated renin cells while preserving RAS inhibition benefits has been established. Natriuretic peptides (NPs) counteract RAS; however, whether NP signaling modulates renin cell activation and afferent arteriolar remodeling remains unclear. METHODSWe examined direct effects of atrial natriuretic peptide (ANP) on As4.1 renin-producing cells using reverse transcription-quantitative PCR, ELISA, and RNA sequencing (RNA-seq). We established a mouse model of long-term RAS inhibition using valsartan, an angiotensin II receptor blocker (ARB), and compared it with sacubitril/valsartan, an angiotensin receptor-neprilysin inhibitor (ARNI). Valsartan was matched between the ARB and ARNI groups. Renin cell activation, afferent arteriolar remodeling, and renal injury were evaluated using biochemical assays, histology, immunostaining, single-nucleus RNA-seq, and region-specific photo-isolation chemistry RNA-seq of afferent arteriolar/juxtaglomerular regions. RESULTSANP suppressed Ren1 expression and renin secretion in As4.1 cells; this effect was attenuated by a natriuretic peptide receptor A antagonist. RNA-seq demonstrated that ANP induced receptor-dependent remodeling of renin cell gene programs. In mice, long-term ARB treatment induced renin cell hyperactivation, expansion of renin-positive juxtaglomerular regions, afferent arteriolar hypertrophy, renal dysfunction, tubular injury markers, and fibrosis. ARNI increased plasma ANP levels and attenuated these pathological changes, despite a comparable blood pressure reduction. Single-nucleus transcriptomics revealed attenuation of tubular injury-associated cellular states and altered renin cell-associated mesenchymal programs with ARNI. Region-specific transcriptomics further demonstrated distinct molecular states in afferent arteriolar/juxtaglomerular regions between ARB- and ARNI-treated kidneys. Integrated transcriptomic analysis suggested that NP signaling converges on vascular regulatory programs in hyperactivated renin-expressing cells. CONCLUSIONSNP signaling acts as a pharmacologically augmentable modulator of maladaptive renin cell activation. ARNI attenuates renin cell hyperactivation, afferent arteriolar hypertrophy, and renal injury during long-term RAS inhibition, suggesting that neprilysin inhibition may preserve RAS blockade benefits while limiting renin cell-driven renal vascular remodeling.

physiology↗

Discovery and structural analysis of glycoside hydrolase family 176 α-1,2 glucosidase from Arthrobacter humicola A8F5

Glycoside hydrolases (GHs) exhibit remarkable specificity dictated by the structural configuration of their target glycosidic linkages. While enzymes that process -1,4- and -1,6-linkages in starch or glycogen are well-characterized, those acting on less common bonds, such as -1,2-glucosidic linkages, remain largely underexplored. In this study, we report the discovery and structural elucidation of a novel -1,2-glucosidase from Arthrobacter humicola A8F5 (A8F5 glucosidase), representing a newly uncovered activity within the poorly characterized GH176 family. Biochemical characterizations revealed that A8F5 glucosidase exclusively cleaves -1,2-linkages via an anomer-inverting mechanism, with a distinct preference for short kojioligosaccharides. To circumvent crystallization obstacles caused by high loop flexibility and translational non-crystallographic symmetry, we engineered a loop-truncated variant. This strategy enabled the determination of high-resolution (up to 1.79 [A]) crystal structures of the enzyme in its ligand-free form and in complex with kojibiose, kojitriose, and selaginose. A8F5 glucosidase adopts a (/)6-barrel fold characteristic of clan GH-G. Complementing the crystal structures with AlphaFold3 prediction demonstrated that two prominent active-site loops (loops 3 and 4) adopt a closed conformation that constricts the catalytic pocket, rendering the architecture suitable for short oligosaccharide recognition while restricting access to larger polymers. Furthermore, sequence similarity network analysis highlights vast, uncharacterized functional diversity within the GH176 family. These findings revealed that the GH176 enzyme recognizes and hydrolyses -1,2-glucosidic bonds through a structural framework distinct from that of the previously known clan GH-L GH65 kojibiose hydrolase, expanding the known functional landscape of this enzyme group toward rare -glucans.

biochemistry↗

Biomechanical regulation of Ca2+ dynamics during muscle stem cell activation

Muscle satellite cells (MuSCs) are muscle-resident stem cells that are responsible for myofiber regeneration. Although the importance of calcium ions (Ca2+) in muscle physiology has been well established, the mechanism by which Ca2+ mobilization governs MuSC function remains poorly understood. In this study, we aimed to systematically characterize Ca2+ dynamics in MuSCs and to define the mechanisms regulating these signals during muscle regeneration. By employing modified protocols for mouse MuSC isolation and Ca2+ measurement, we observed spontaneous Ca2+ fluctuations in MuSCs isolated from regenerating muscle after cardiotoxin-induced myofiber injury. Our detailed analysis using chemical Ca2+ indicators and a genetically encoded Ca2+ indicator revealed that the frequency and amplitude of Ca2+ fluctuations increased significantly during the activated and proliferative stages of MuSCs in muscle regeneration. This effect was more pronounced in MuSCs isolated from dystrophic and aged mice. Mechanistically, these Ca2+ fluctuations were at least partially mediated by mechanosensitive ion channels, including PIEZO1 and TRPM7, which promote MuSC migration. Collectively, our findings demonstrate that Ca2+ fluctuations through mechanosensitive ion channels act as a key regulator of MuSC activation during muscle regeneration and may provide new insights into the role of Ca2+ influx in muscle biology and the pathogenesis of muscle diseases.

cell biology↗

Machine learning-based decoding of emotional valence from electrophysiological signals in the monkey brain

Understanding how the brain operates in naturalistic settings requires methods that go beyond conventional repeated-measurement approaches, necessitating the development of single-trial neural activity analysis. Recent advances in machine learning offer new opportunities for analyzing brain electrophysiological signals. Here, we recorded surface electrocorticography (ECoG) and intracranial local field potentials (LFPs) from emotion-related brain regions in a monkey performing a Pavlovian conditioning task, in which sensory cues predicting reward or punishment were presented randomly, followed by the actual unconditioned outcome. We evaluated the performance of two machine learning algorithms, a Convolutional neural network (CNN) model and a Transformer-based model (EEG-Conformer), in classifying raw ECoG/LFP traces. Both models successfully classified valence type during conditioned and unconditioned stimulus presentation. Furthermore, the Transformer achieved significantly superior classification performance compared to the CNN, particularly in multi-state classification including baseline periods. By optimizing the training dataset for the Transformer model, we could detect dynamic fluctuations in emotional valence consistent with task type from continuously evolving ECoG/LFP patterns recorded throughout the task. These results demonstrate the utility of Transformer-based models for decoding emotional valence from neurophysiological signals in non-human primates.

neuroscience↗

11β-HSD2 buffers fetal glucocorticoid exposure inducing Per1 expression under maternal stress

Glucocorticoids (GCs) have been proposed as maternal-fetal communication signals. However, fetal circadian rhythms are initially shielded from maternal entrainment, in addition to delayed circadian clock emergence due to CLOCK suppression. Premature CLOCK/BMAL1 activation disrupts Hes7-driven somite-like structure in gastruloids. Given the genomic proximity of Per1 to Hes7 and their transcriptional ripple effect, the physiological significance of delayed cell-autonomous circadian clock development and the temporal program of maternal-fetal communication during the developmental process have remained unclear. Here, based on a marked decline in Hsd11b2, encoding a GC-inactivating 11{beta}-HSD2 enzyme, during organogenesis, we performed split-litter embryo-transfer experiments in which Hsd11b2 knockout (KO) and wild-type (WT) embryos shared the same maternal environment. Amniotic fluid (AF) GCs remained low and arrhythmic under basal conditions. In contrast, maternal stress caused a pronounced GC surge and Per1 induction in KO, suggesting that 11{beta}-HSD2 buffers acute maternal GC surges. Despite the genomic proximity of Per1 to Hes7 and their transcriptional ripple effect, stress-associated and pharmacological GC exposure recapitulated no overt segmentation defects in vivo. Embryonic stem cell-derived gastruloid assays confirmed that neither GC exposure nor Per1 induction arrested Hes7 oscillations, whereas premature CLOCK/BMAL1 activation impaired these processes even in Hes7 KO gastruloid with ectopic rescue, suggesting that interference with the segmentation clock is mediated by premature CLOCK/BMAL1 activation, not by GC-induced Per1 expression. These findings clearly show that maternal GC signals are selectively buffered during early development. In addition, suppression of CLOCK/BMAL1 activity preserves segmentation clock function, indicating delayed circadian clock emergence is actively regulated during embryogenesis. Significance StatementGCs have been proposed as maternal-fetal communication signals. However, initially, circadian clock is not only suppressed but also shielded from maternal entrainment. Premature CLOCK/BMAL1 activation can disrupt Hes7-driven somitogenesis. In a split-litter Hsd11b2-knockout model, AF GCs remained low and arrhythmic basally but surged after maternal stress in KO embryos, inducing Per1. Despite a genomic position effect of Per1-Hes7 and their putative transcriptional coupling, stress-associated or pharmacological GC exposure did not cause segmentation defects in vivo or disrupt Hes7 oscillations in vitro, whereas CLOCK/BMAL1-driven arrest of Hes7 oscillations persisted in gastruloids despite ectopic Hes7 rescue. These findings identify 11{beta}-HSD2 as a developmental buffer and support the physiological importance of the temporal architecture controlling the timing of circadian clock development.

developmental biology↗

Ropinirole hydrochloride mitigates oxidative stress and neuroinflammation via the PI3K-mTOR pathway in TDP-43 hiPSC-derived microglial-like cells

BackgroundAmyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder characterized by progressive motor neuron loss accompanied by neuroinflammation, oxidative stress, and impaired proteostasis, with pathological aggregation of TDP-43 as its defining hallmark. Microglia are recognized as central contributors to ALS pathogenesis, yet the mechanisms underlying their intrinsic dysfunction in the context of TDP-43 remain insufficiently characterized. MethodsWe characterized microglia-like cells (iMGLs) differentiated from isogenic TDP-43 M337V human induced pluripotent stem cell lines. We performed integrated functional assays, transcriptomic profiling and drug repurposing analysis to systematically compare mutant and control iMGLs. To assess therapeutic potential, we evaluated the effects of ROPI, a dopamine D2 receptor agonist previously advanced to clinical trials for ALS, on disease-relevant phenotypes in TDP-43 iMGLs. ResultsTDP-43M337V/M337V iMGLs presented ALS-associated abnormalities, including cytoplasmic TDP-43 accumulation with impaired phagocytosis and elevated oxidative stress, impaired autophagy and mitophagy, altered cytokine profiles, and reduced ferritin levels. Building on our previous identification of ropinirole hydrochloride as neuroprotective for ALS motor neurons, we now show that it confers therapeutic benefits in mitigating microglial pathology. ROPI treatment significantly reduced oxidative stress and caspase-3/7 activity and partially restored cytokine homeostasis in TDP-43M337V/M337V iMGLs, independent of autophagy/mitophagy modulation. Transcriptomic profiling revealed that ropinirole modulated disease-associated gene expression signatures involving protein folding, extracellular matrix organization, and oxidative stress responses. Furthermore, connectivity map-based analysis prioritized PI3K-Akt-mTOR inhibitors as candidates for reversing TDP-43 iMGL signatures, and ropinirole was found to modulate mTOR signaling. These converging lines of evidence support a mechanistic role for ropinirole in restoring microglial homeostasis via PI3K-mTOR pathway regulation. Taken together, our findings position ropinirole as a promising candidate dual action therapeutic candidate capable of targeting both neuronal and microglial dysfunction in ALS, suggesting broader applicability of ropinirole in modulating neuroinflammatory cascades across other neurodegenerative conditions. ConclusionRopinirole broadens ALS therapy from motor neurons to microglia, underscoring its promise for integrated and clinically meaningful treatment strategies.

neuroscience↗

A Symmetric Systemic Challenge Elicits a Right-Biased Response Mediated by Vasopressin Signaling

Bilaterian animals exhibit operational (functional) asymmetry--population-level, directional left-right differences in physiology and behavior, including responses to spatially symmetric environmental challenges. Whether such symmetry-to-asymmetry conversion can be driven at the systems level by neurohormonal regulators remains unclear. Here we tested whether a spatially symmetric neuroendocrine challenge--water deprivation (WD)--can elicit a directional left-right physiological response in rats using hindlimb postural asymmetry (HL-PA), a binary readout that quantifies left- versus right-sided hindlimb flexion. Twenty-four hours of WD induced robust HL-PA with right hindlimb flexion, revealed under anesthesia. The asymmetry persisted after complete thoracic spinal cord transection, suggesting that humoral signaling, rather than descending neural commands, may maintain the postural bias. Because dehydration recruits the hypothalamic-neurohypophysial arginine vasopressin (AVP) system, we next tested AVP receptor involvement. Both a V1B antagonist (SSR-149415) and a V1A/V2 antagonist (conivaptan) abolished WD-induced HL-PA, supporting an AVP-dependent mechanism that likely operates at least two anatomical sites. AVP signaling may involve pituitary V1B-dependent endocrine output and spinal V1A actions; consistent with the latter, expression of AVP V1A receptors is right-biased in lumbar spinal cord. Together, these findings identify WD as a symmetric systemic challenge capable of imposing a directional peripheral set-point, and implicate vasopressin signaling in symmetry breaking and left-right physiological regulation. Visual summary O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=133 SRC="FIGDIR/small/708998v1_ufig1.gif" ALT="Figure 1"> View larger version (36K): org.highwire.dtl.DTLVardef@10d6b3corg.highwire.dtl.DTLVardef@1fb4b5aorg.highwire.dtl.DTLVardef@11003c0org.highwire.dtl.DTLVardef@66671c_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

Hypothalamic asymmetry in hemisphere-specific neuroendocrine signaling

Brain lesions classically cause contralateral sensorimotor and postural deficits, attributed to the decussation of descending neural pathways. However, recent findings reveal that, beyond neural mechanisms, contralateral effects can also be mediated by the neuroendocrine system via humoral pathways. This raises the possibility that the brain regulates left- and right-sided peripheral processes through hypothalamic neurohormones released into the bloodstream. For such spatially targeted endocrine signaling to occur, hemisphere-specific neural activity must be encoded into side-specific hormonal output--requiring a lateralized organization of hypothalamic neuroendocrine systems. Here, we report molecular asymmetries in the rat hypothalamus that support this mechanism. Transcriptomic analysis revealed asymmetric expression of eleven neurohormonal genes, including Gnrh1, Cck, and Trh, along with distinct left-right side-specific gene co-expression networks. Chemogenetic stimulation of Arg-vasopressin neurons in vasopressin-hM3Dq-mCherry transgenic rats produced generalized changes in these networks--predominantly in the right hypothalamus--suggesting that hypothalamic neurohormonal circuits function as integrated, lateralized ensembles. Stereological analysis revealed asymmetric coordination of vasopressin neurons within the paraventricular nucleus, with the left rostral region decoupled from the right rostral and caudal subregions. Functionally, gonadotropin-releasing hormone, cholecystokinin-8, and thyrotropin-releasing hormone--administered intracisternally in rats with complete spinal cord transection--elicited side-specific peripheral responses, measured as hindlimb postural asymmetry in a binary left-right output model. These neurohormonal effects were therefore transmitted via the humoral route. These findings suggest that multiple hypothalamic neurohormones and their integrated networks are asymmetrically organized, and that their lateralization may be necessary for hemisphere-specific hormonal regulation of peripheral systems.

neuroscience↗

The emergence of intentional action in early human infancy

Intention lies at the core of human behavior, allowing flexible and goal-directed interaction with the environment. However, how it emerges in infancy remains poorly understood. Here we show that intentional action can emerge before overt reaching, revealing that 3-month-old infants display pupil dilation preceding self-initiated actions during interaction with a suspended mobile toy. This phasic pupil dilation first appeared after movement onset but gradually shifted to precede it through environmental interaction, reflecting the emergence of action preparation and prediction of action outcomes. This shift also implies that infants are capable of anticipating the timing of their forthcoming movements. Furthermore, the antecedent pupil dilation occurred only with efficient movements characterised by reduced muscle co-contractions. These findings suggest that infants learn to predict outcomes of their own actions and initiate particular movements at self-determined timings, marking the emergence of intentional action.

neuroscience↗

Hypoxia-induced gene expression changes in N. vectensis embryos

Oxygen availability is one of the critical drivers of metazoan evolution and diversification. The earliest metazoans evolved in shallow marine shelves of the Neoproterozoic era, where the redox environment was likely variable and spatially heterogenous. This imposed physiological constraints on the emerging animals, selecting for oxygen-responsive and stress-adaptive traits. Embryogenesis is a novel and highly conserved stage of metazoan development, and its regulatory architecture may hold the key to understanding how adaptive traits arise in response to environmental change. Defining how early metazoan embryos respond to fluctuating oxygen levels will therefore provide essential insights into the adaptive mechanisms that shaped the evolution of metazoans. Here, the embryos of the cnidarian Nematostella vectensis, a representative of early-diverging metazoans, were used to comprehensively investigate the developmental and genetic responses to hypoxia. N. vectensis embryogenesis is oxygen-dependent, with hypoxia inducing a reversible developmental arrest. Transcriptomic profiling reveals that the hypoxia response in N. vectensis embryos is conserved with bilaterians, encompassing core hypoxia-responsive genes and pathways. These findings suggest that the genetic toolkit underlying embryonic hypoxia responses was already established in the common cnidarian-bilaterian ancestor.

evolutionary biology↗

Tegmental atrophy in isolated REM sleep behaviour disorder: Ex vivo-informed in vivo imaging

Isolated rapid eye movement (REM) sleep behaviour disorder (iRBD) is an early-stage synucleinopathy characterized by brainstem pathology. In rodents, the pontine tegmentum contains an REM sleep centre, the sublaterodorsal nucleus (SLD), which expresses corticotropin-releasing hormone binding protein (CRHBP). While the involvement of brainstem pathophysiology is thus implicated in iRBD, its solid evidence remains scarce in humans due to the difficulty in identifying small brainstem nuclei with conventional MRI technology alone. Here, we aimed to detect tegmental atrophy in iRBD with voxel-based morphometry (VBM) analysis combined with a novel human brainstem atlas. Structural MRIs from 98 patients with iRBD and 114 controls were analysed to investigate grey matter volume (GMV) using VBM. Our unique approach involved detailed assessments of the VBM results, guided by a high-resolution MRI-based atlas of the human brainstem. This brainstem atlas was founded on ex vivo MRI of 10 postmortem human specimens. We validated it with CRHBP immunostaining, which aided in identifying putative REM sleep-regulating nuclei in humans. We applied this brainstem atlas to identify atrophy in specific brainstem regions in iRBD and correlate their volumes with clinical measures, including autonomic functions. VBM revealed a focal cluster of grey matter atrophy in the dorsal pontine tegmentum of iRBD patients, including the laterodorsal tegmental nucleus, ventral part (LDTgV) and the pedunculopontine tegmental nucleus (PTg). Our atlas-based analysis confirmed the LDTgV as the site of most conspicuous atrophy, revealing a significant volume reduction in iRBD patients compared to controls with a moderate effect size (Cohens d = 0.46, Bonferroni-corrected p = 0.019). Furthermore, greater atrophy in the LDTgV and the PTg was associated with more severe autonomic dysfunction as measured by Scales for Outcomes in Parkinsons Disease-Autonomic dysfunction (SCOPA-AUT) scores (partial r = -0.237, p = 0.019 and partial r = -0.236, p = 0.019, respectively). Histological analysis confirmed that the LDTgV is selectively enriched with CRHBP-positive neurons, a putative marker for REM sleep-on neurons. We provided novel evidence for the involvement of LDTgV, the putative human homolog of the murine SLD, in iRBD. The present findings advance our understanding of the neuroanatomical basis of iRBD and will contribute to the development of early biomarkers for -synucleinopathies.

neuroscience↗

Metabolic Trans-Omic Analysis Reveals Key Regulatory Disruption of Energy Metabolism in Alzheimer's Disease

Alzheimers disease (AD), a leading cause of dementia, has been recognized as a disease with profound metabolic dysregulation. However, a systems-level view of metabolic regulation across multiple omic modalities in AD remains elusive. Here, we integrated public multi-omic datasets (transcriptome, proteome, and metabolome) from the dorsolateral prefrontal cortex of AD patients and controls. By leveraging existing molecular biological knowledge, we reconstructed a multi-layered metabolic regulatory network to systematically map the potential interplay among mRNAs, proteins, and metabolites in AD. Our analysis revealed a putative coordinated downregulation of energy producing pathways, including the TCA cycle, oxidative phosphorylation, and ketone body metabolism, driven by reduced enzyme abundance and inhibitory allosteric effects. In contrast, the glycolysis pathway appeared to be influenced by opposing enzymatic and allosteric regulations. These findings highlight key metabolic dysregulations that may contribute to the bioenergetic deficits in AD.

systems biology↗

Functional impact of pathogenic Runt domain mutations in Runx2 in vivo: Insights into the skeletal and dental anomalies of cleidocranial dysplasia

Runt-related transcription factor 2 (RUNX2) is essential for skeletogenesis, and mutations in its gene cause cleidocranial dysplasia (CCD), an autosomal dominant skeletal disorder. The evolutionarily conserved 128-amino acid Runt homology domain (RHD) of human RUNX2 is essential for DNA binding and heterodimerization, and serves as a mutation hotspot associated with severe CCD phenotypes. To elucidate the functional impact of pathogenic RHD mutations in vivo, we generated two novel mouse lines: one carrying a missense mutation, c.695G>A (p.R232Q) (Runx2m/+), corresponding to the human RUNX2 c.674G>A (p.R225Q), and the other harboring a frameshift mutation, c.697_698delGA (p.E233TfsTer9) (Runx2112/+), causing a premature stop codon. Homozygous Runx2m/mand Runx2112/112 mice lacked membranous ossification, whereas heterozygous Runx2m/+ and Runx2112/+ mice displayed typical CCD-like skeletal features, including an open anterior fontanelle and clavicle hypoplasia. Unexpectedly, heterozygotes carrying pathogenic mutations in RHD developed an accessory root-like protrusion at the furcation of three-rooted maxillary first molars, representing a previously unrecognized dental phenotype during root development. Dual luciferase assays revealed impaired transactivation of the p.R232Q mutant Runx2 on the osteocalcin enhancer/promoter. Wild-type Runx2 was robustly expressed in osteoblasts and hypertrophic chondrocytes during bone formation, but the mutant Runx2 exhibited reduced expression in hypertrophic chondrocytes and partially impaired nuclear localization, resulting in arrested osteoblast and chondrocyte maturation. Our mutant mouse model provides a valuable in vivo platform to study CCD pathogenesis, mechanisms of tooth root furcation, and therapeutic interventions targeting dysfunctional RHD.

genetics↗

Involvement of orexin nerves in early stage of Alzheimer's disease model mice and preventive effect of orexin receptor antagonists

BackgroundMild cognitive impairment (MCI) is a condition between healthy cognition and dementia with a high probability of progression to Alzheimers disease (AD). Elevated levels of orexin (OX) have been reported in the cerebrospinal fluid of patients with MCI and AD. ObjectiveTo investigate the efficacy of dual OX receptor antagonists (suvorexant and lemborexant) in an early-stage AD mouse model (App-KI). MethodsThe expression of the OX receptor gene, the levels of suvorexant and lemborexant in the brain after a single oral dose, and their effects on locomotor activity were investigated in wild-type mice. In addition, the cognitive function of wild-type and App-KI mice was assessed using the Y-maze test after oral administration of suvorexant or lemborexant once a day for 60 d. After the behavioral test, amyloid-beta levels were quantified in the hippocampal CA1 region of App-KI mice. ResultsThe expression of the OX receptor gene was highest in the lateral hypothalamus and was also observed in other brain regions. Drug levels peaked at 20-40 min for suvorexant and 15 min for lemborexant and declined, still detectable 24 h later. Locomotor activity was reduced after suvorexant or lemborexant administration; however, 24 h after administration, locomotor activity did not differ from the control group. In particular, the Y-maze test showed that suvorexant and lemborexant prevented cognitive impairment in App-KI mice. Furthermore, suvorexant and lemborexant suppressed amyloid-beta accumulation in the hippocampal CA1 region of App-KI mice. ConclusionThe results suggest that suvorexant and lemborexant effectively suppress the early stages of AD.

animal behavior and cognition↗

Neural Maturation Provides the Stability of Representation and the Solution for Understanding Complex Concepts

Neural maturation must preserve flexible state dynamics while preventing those dynamics from becoming unstable, unreadable, or mismatched to learning. Here, I identify KCNH7, encoding the ERG3/Kv11.3 potassium channel, as a maturation-associated candidate regulator of such operating regimes. Public developmental, single-cell, and Patch-seq analyses linked KCNH7/ERG3 to late postnatal expression and passive-state electrophysiological axes. In conductance-based Purkinje-cell models, ERG3/KCNH7-like conductance increased the threshold for tonic firing while broadening pre-tonic response classes and enhancing target-specific rhythmic recruitment, indicating a regime shift rather than a simple excitability brake. KCNH7-inspired adaptive dynamics stabilized spiking learning and reshaped high-load associative retrieval beyond scalar threshold or temperature control. In recurrent conductance reservoirs, ERG3/KCNH7 scale and half-activation voltage tuned driven dynamical regime, spike-state versus voltage-state memory, and temporal-context-dependent prediction. Under degraded state transmission, moderate WT-like ERG3/KCNH7 conductance converted a vulnerable high-dynamic baseline into a low-fidelity support regime. Public in vivo population and behavioral analyses further supported the view that maturation- and disease-related phenotypes can be interpreted as alterations in operating-regime control rather than simple changes in activity or sensory performance. These results support KCNH7/ERG3 as a model case for linking ion-channel maturation to stable yet flexible neural computation.

neuroscience↗

Field-crop transcriptome models are enhanced by measurements in systematically controlled environments

Plants in the field respond to seasonal and diel changes in various environmental factors such as irradiance and temperature. We previously developed a statistical model that predicts rice gene expression from the meteorological data and identified the environmental factors regulating each gene. However, since irradiance and temperature (the two most critical environmental factors) are correlated in the field, it remains difficult to distinguish their roles in gene expression regulation. Here, we show that transcriptome dynamics in the field are predominantly regulated by irradiance, by the modelling involving diurnal transcriptome data from the 73 controlled conditions where irradiance and temperature were independently varied. The models prediction performance is substantially high when trained using field and controlled conditions data. Our results highlight the utility of a systematic sampling approach under controlled environments to understand the mechanism of plant environmental response and to improve transcriptome prediction under field environments.

plant biology↗